Several times in this article you hear the converts speaking of a desire to become more humble and disciplined. I think an unstated reason is because they're looking for some purpose or reason for their life and even a challenge or a test that they must pass with courage. Now this all sounds weird coming from a believer of Christ like myself, but I can see it.
What people do not realize is that there is a growing backlash in the hearts of many, particularly the young, against the anything-goes, there-is-no-absolute-truth culture that has been developed in this country over the last century. Moral relativism as well and tolerance of all religions as equal has led people to search for a religion that makes clear to them exactly what they should and should not do and which fearlessly holds itself out to the world proclaiming that it is the true way and no other.
What is saddest of all is that Christianity is, in its true form, the ultimate in all of those things but its people have lost their way. We huddle into churches (or not) and listen to some paid preachers of words that tickle our ears rather than the true meat of God's word. We look at and listen to nearly every form of fornication, blasphemy, excess, and immorality on television and radio and laugh and love it. Then we tolerate it in our family, our friends, our brotherhoods, and even in ourselves. We look at those among us who are willing to suffer shame for what is right and who speak out against this evil as weirdos and "dorks".
We are terribly proud of ourselves too. The idea of the importance of the individual has been taken to a hedonistic extreme where each person can feel fully justified in satisfying himself at the expense of all others because no one has the right to tell him how to govern his morality. We think that our God-given power and prosperity is eternal and can never be challenged as long as we live. Even those who admit that their children and grandchildren may yet live to see a terrible civil war will even yet not try to do anything to change things. They continue on their own path to destruction and try to lead their children and grandchildren with them.
But the children are not following as planned. Many are turning into another path to destruction: the bonds of Islam. They see in it at least a religion which makes things clearly defined and is not at all relative but which gives them a path and a purpose and above all something to die for---something to believe in.
They do not see that the true path and the true reason for life is the one which they have heard of many times as a child and yet have never truly been shown: Jesus the Christ of God. It is human error spurred on by selfishness, greed, and the evil promptings of the Deceiver himself which leads those who raised them or are friends of theirs to misportray Christianity and Christ by living a false life themselves.
And so they search on, and find their own destruction.
And people like me keep searching too---asking God constantly and fervently to take us deeper and deeper into Christ and the truth of all things...and asking God to lead back our friends whose hearts have been deceived.
Same reason Nazism and other totalitarian ideals catch hold. Some people want all the answers to life handed down to them, ambiguity is not something the masses handle well.